One of the more important factors in golf club equipment is the club shaft. The shaft transfers the golfer's power to the club head. Golf club shafts are available in various types of materials and structures. Steel shafts are stronger, last longer, more durable and generally less expensive than graphite or carbon fiber shafts, and are usually made from carbon steel, although stainless steel is sometimes used. The steel shafts are available in stepped or rifle designs. The graphite shafts are more expensive and less durable; however, the lighter weight creates greater swing speed for more power. Also available are multi-material and titanium shafts.
When installing a shaft, the proper length must be accurately determined. The length can be as important to a golf shaft as is the flex or torque. Most measurements of the correct shaft length for the player involve a determination of a particular player's height and distance of his hands to the floor. Shaft length will impact whereon the clubface the ball will be consistently struck, and often, an incorrect shaft length is the main cause of a golfer to alter his natural swing arc in order to make optimum impact. According to most research, if ball impact is but one inch off-center this can equate to a 14% loss of carry distance, so it is vitally important that the length of the club be accurately fitted for each particular player.
If it is seen in the fitting process that a player needs to adjust his club length, such as adding or removing a half inch, inch or two inches to the length of the club, it would be highly desirable to lengthen his present club(s) rather buy and install new shafts. Typical driver shaft lengths are from 43 to 47 inches.
Prior art shafts having adjustable lengths have been used for many years for a wide variety of applications. Each of these applications has its own functional and aesthetic requirements for the shaft construction which is employed. As a consequence, a number of different mechanisms and devices have been developed to satisfy the particular application requirements. A majority of golf club shaft extension patents are directed to use mainly as putters, or to extending shafts of an existing set of clubs to accommodate growing children. While the teachings of the present invention may be adapted to these types of applications, the focus is rather to make a club adjustment that is rigid, secure, and easily fastened. Additionally, the ability to adjust the shaft length without the need for a custom grip or a custom made shaft is desirable along with the device being hidden within the shaft and grip such that it is not distracting to the player.